There are Critical nuclear weapons design information that Trump had access to, he bragged about the contents of the CNWDI documents on several accessions. The fusing and firing system to the new SLBM and ICBM warheads, the exact modifications to the B61-12 and B83 are three of the things that might have been compromised.
Still skeptical about those nuclear codes are ya? I'd put nothing out of bounds with Trump. I suspect people misunderstand Trump's psychology. He actually hates America, despite his flag hugging. Why? He's a bad businessman who thinks he should be like Musk and Zuckerberg, but he's not. He has had to borrow money from foreign crooks to maintain his veneer of a wealthy man. He resents America, because it hasn't allowed him to be the business genius he believes he is. He wants to hurt America due to this grievance, with the result of being installed as a dictator with a family line of succession of future dictators. All Trump's betrayal of US national security makes perfect sense from this psychological perspective.
Nuclear...............2 choices I think considering who has something over Trump.
Israel has had nuclear weapons since the 1960s according to information from Jane's. They currently have between 80 and 400 weapons and every country in the world knows it. They are a non signatory to the Nonproliferation Treaty, so there is no blackmail possibility for Israel. The Israelis and Saudis are now allies against Iran.
@glennlab This is all speculation, but nuclear secrets between Israel and the USA would be embarrassing, especially the treatment of other countries for non-compliance.
All we really know is top secret/ nuclear and archived. Could be to do with Fukushima for all we know. Maybe depleted ammo use...........